1. Field of the Invention
The present invention relates to an electric vehicle in which an output of a motor is transmitted to an axle through a reduction mechanism, thereby rotating a wheel.
2. Description of Background Art
In the past, various electric vehicles have been proposed in which an output of a motor is transmitted to an axle through a reduction mechanism, thereby rotating a wheel.
For example, in JP-A No. 2008-100609, there is proposed an electric vehicle in which, on one side of a wheel, a motor and a reduction mechanism are built into a swing arm, and a brake is provided within the wheel, while on the other side of the wheel, an axle passing through the wheel is supported by an auxiliary arm, thereby supporting the wheel and the axle with a double-sided swing arm.
In the electric vehicle disclosed in JP-A No. 2008-100609, both sides of the wheel and axle are supported by the double-sided swing arm. However, since the motor and the reduction mechanism are disposed on a side (one side) of the wheel, a heavy load is applied to only one side of the wheel. Therefore, it is necessary to reinforce (increase in stiffness) the portion of the swing arm on the side on which the motor and the reduction mechanism are located, and make the auxiliary arm heavier for weight balance between the left and right sides.
In this manner, in the electric vehicle disclosed in JP-A No. 2008-100609, the heavy load is supported on one side of the swing arm and the other side is supported by the auxiliary arm. Unfortunately, therefore, this structure cannot sufficiently offer the advantage of the double-sided swing arm of supporting a drive system, such as a motor, and a wheel on both sides while achieving weight balance.
Also, in the electric vehicle disclosed in JP-A No. 2008-100609, the swing arm is composed of a rear arm body that supports the wheel and the drive system, a cover that closes the left side of the rear arm body, and the auxiliary arm that closes the right side thereof. In this case, the axle passes through the rear arm body in a vehicle width direction. A wheel assembly (a wheel assembly including the wheel and a tire), including the wheel through which the axle passes, is supported between the right side of the rear arm body and the auxiliary arm. Also, the reduction mechanism with the axle passing therethrough, and the motor are supported between the left side of the rear arm body and the cover. The brake is disposed at a portion of the rear arm body in the vicinity of the axle.
Therefore, when removing the wheel assembly and the motor from the electric motor, it is necessary to remove the motor in the condition where the cover is removed, and on the other hand, to remove the wheel assembly in the condition where the auxiliary arm is removed. In other words, according to JP-A No. 2008-100609, it is necessary to firstly remove the cover and the auxiliary arm and then remove the motor and the wheel assembly separately in different directions. It is therefore impossible to remove the wheel assembly and the motor in one direction, leading to a reduction in operational efficiency. On the other hand, when mounting the wheel assembly and the motor on the electric vehicle, it is also necessary to firstly mount the wheel assembly and the motor and then cover with the auxiliary arm and the cover, respectively. Also in this case, therefore, the operational efficiency is reduced.
Accordingly, the present invention has been made in view of the problems in the related art, and an object of the present invention is to provide an electric vehicle in which weight balance is easily achieved and which allows an improvement in the operational efficiency of mounting, removal, and replacement (both of removal and mounting) of a wheel and a motor.